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Full text of "Diseases Of The Nose Throat And Ear"

PHYSIOLOGY OF THE VEST1BULAR APPARATUS         273

is to the right while the real vestibular component is the slow return to the
left. Nystagmus is always most marked when the patient looks in the direction
of the quick component, and is lessened or abolished when he looks in that of
the slow component. Nystagmus which is present only when the patient looks
in the direction of the quick component is known as nystagmus of the first
degree\ if nystagmus is also present when the patient looks straight in front it
is said to be of the second degree \ if still present when he looks in the direction
of the slow component, the nystagmus is of the third degree. A patient with
nystagmus to the right is requested to look at an object on his right side. The
vestibular pull causes the eyes to deviate to the left. Under the influence of an
anaesthetic the quick component of nystagmus is eliminated, and the slow
or vestibular movement alone takes place, and results in conjugate deviation.
Spontaneous Pointing. Orientation means the determination of the relation of
the body to space, while equilibration means the maintenance of position
whether walking, standing or sitting. Pointing is a voluntary act by which the
patient indicates his sense of orientation. The normal person is always aware
of the location of his hand or finger in space and, with his eyes closed, is aware
of the exact position of objects previously located with the finger. In carrying
out Barany's pointing test, the patient is seated and the examiner stands
opposite to him. The patient shuts his eyes and extends one upper extremity
with three fingers and thumb closed but the forefinger pointing forwards. The
examiner also extends his hand and brings one forefinger below and in contact
with that of the patient. At the word *Up* the patient raises his arm to the
vertical position, and then immediately brings it back again to touch the
examiner's finger. In the same way downward and lateral pointing may be
tested. Further, the accuracy of pointing at the elbow- and wrist-joints and
also in the joints of the lower extremities may be investigated; even the
pointing reaction of the head and trunk may be tried; but, as a rule, only the
reactions of the upper extremities are examined.

Spontaneous Falling (Romberg's Test). The patient stands with heels and toes
together and eyes closed, and the direction of any swaying or falling is noted.
The patient is now asked to turn his head sharply to the right or left, and any
change in the direction of falling is noted. The examiner now grasps the
shoulders of the patient and attempts to over-throw him either to one side or
the other, forward or backward. The patient is told to balance himself so that
he will not fall. When the shoulders of the patient are pressed towards the
right, the pelvis should sway towards the left in the attempt to maintain
equilibrium.

Positional Nystagmus. Nystagmus, usually rotatory and accompanied by
rotatory vertigo, may occur only in certain positions of the head; commonly
in the recumbent position with the head extended and turned to one side. The
patient can frequently assume the position in which vertigo is experienced.
Changes in position of the head must be effected by slow movements in order
to elicit a 'position' reflex due to movement. The presence of positional
nystagmus is probably an indication of disturbance of the vestibular systemó
inner ear, vestibular nerve or brain centres.

Positional nystagmus has been divided into Nylen type 1, in which
nystagmus changes direction on the assumption of different head positions;
and Nylen type 2, in which nystagmus is always in the same direction but only
occurs in certain head positions. Finally, it is classified asfatiguable, indicative